This invention relates to a fluid containment device and more particularly to a dual containment fitting that protectively seals a portion of pass-through tubing.
There are a number of existing dual containment-type fittings such as those disclosed in U.S. Pat. Nos. 2,983,506, 4,871,196, and 3,861,719. Each of these patents describes inner tubing surrounded by an outer containment tubing. However, in each of these cases the inner tubing is not a true pass-through tubing but rather a tubing that terminates at the fitting creating the risk that the inner tubing may form a leak between itself and the fitting. While the outer containment tubing is there to collect any leakage, a true pass-through tubing would eliminate this risk leaving the outer containment tubing to handle only those leaks that are due to damage and/or wear to the inner tube rather than those leaks caused by a poor fitting connection.
U.S. Pat. No. 5,498,036 discloses in FIG. 5 a dual containment fitting that is mounted to the wall of an instrument cabinet. The outer containment tubing is attached to the fitting while the inner tubing passes through the outer tubing, the fitting, and into the instrument cabinet. The portion of the fitting that extends into the instrument cabinet leaves the bore, through which the inner tubing passes, open to the cabinet creating potential for danger to the instrument cabinet components. The outer tubing will contain leakage from the inner tubing, however, the level of fluid contained in the outer tubing may rise to a level such that fluid seeps into the bore surrounding the inner tubing. The fluid may continue to seep forward until it reaches the end of the bore and pours into the instrument cabinet damaging the instruments within.
Further, U.S. Pat. No. 5,498,036 provides no manner in which to fixedly position the inner tubing. Rather, the inner tubing is left to slide freely within the fitting and outer tubing.
In view of the above, there is a need for dual containment fitting that incorporates a true pass-through inner tubing to eliminate the possibility of leakage at the connection point of the inner tubing and the fitting. Further, it is desirable that this fitting provide for sealed protection at both ends of the fitting bore and that the fitting provide a manner in which the inner tubing may be fixedly positioned.